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ERNST PREISWERK, or BASEL, SWITZERLAND, assrenoa TO THE HOFFMAIxTN-LA I ROCHE CHEMICAL WORKS, or NEW YORK, N. Y., A oonroaarron on NEW YORK.

EASILY AND NEUTRALLY SOLUBLE DOUBLE COMPOUNDS O13 l-ALLYL-Sfi-DIMETI-IYL- XANTHINE.

No Drawing. Application filed June 9,

To all whom it may concern.

Be it known that I, ERNST Pn IswE-RK, a citizen of Switzerland, and. a resident of Basel, Switzerland, have invented certain new and useful Easily and Neutrally Soluble Double Compounds of 1-Allyl-3 fT-D imethylxanthine, of which the following is a specification.

My invention relates to easily and neutrally. soluble double compounds of 1 allyl-3.T-dimethylxanthine which may be produced by allowing at least 2 molecules of an alkali salt of the benzol-carbonic acids to act upon 1 molecule of 1-allyl-3.7-dimethylxanthine.

It'is known that 1-3-'7-trimethylxanthn1e and the alkali Salts of benzoic and salicylic. acid form easily soluble compounds containing the two components in molecular proportions (Hager, Handbuch der Pharmaceutischen Praxis, 1913, vol. 1, page 912). The manufacture of easily soluble double compounds of l-ethyl-3.7-dimethylxanth1ne with the alkali salts of benzoic and salicylic acid in molecular proportions is described in the German Patent No. 170302. By replacing the methyl or ethyl radical by the allyl group thecharacter ot the compound is so materially altered that it is not possible to obtain an easily Soluble product by the treatment with an alkali salt of the hen zoic or salicylic acid in molecular proportions. It was however desirable that 1- allyl-3.T-dimethylxanthine should be rendered soluble in water in order. to make it suitable for injections.

It has been found that easily and neutrally soluble double compounds of l-allyl- 3.7-dimethylxanthine may be obtained by allowing at least 2 molecules of an alkali salt of the benzol-carbonic acids to act upon 1 molecule of 1-allyl-3.7 -dimethylxanthine. The new double compounds are best obtained by evaporating the solutions in vacuo.

These compounds are easily soluble in water, particularly in warm water. Their dilute aqueous solution reacts neutrally and is not altered by the addition of alkali. The addition of mineral acids to moderately dilute solutions of these compounds produces a White crystalline precipitate. Upon intense heating these compounds leave a solid residue of alkaline reaction. It is thus pos sible to obtain a diuretic of the qualities of 1921. Serial No. 476,307.

theobromine, which at the same time has the analeptic properties of cali'eine, in neutral aqueous solution and of a concentration suitable tor injection.

The new con'ip'ounds are to be use in therapy owing to their excellent diuretic and analeptic properties.

Example 1.

22 parts of 1-allyl-3.7di1nethylxanthine and 33 partsof sodium salicylate are dissolved in 110 parts or" water. After evaporation in vacuo 30 per cent solutions may easily be obtained from the remaining compound. Even when left standing for some time in a normal temperature no crystals separate from these solutions.

Era 172 7) Z6 2.

22 parts of 1-allyl-3.7-dimethylxanthine and 39 parts of lithium benzoate are dissolved in 220 parts of warm water and the solution is evaporated in vacuo. On being taken up in water the compound thus ob tained yields stable, neutral solutions.

Example 3.

22 parts of 1-allyl-3.7-dimethylxanthine and 58 parts of sodium benzoate are dissolved in 220 parts of water. On being evaporated in vacuo the clear solution leaves a white crystalline residue from which at normal temperature 10 and higher per cent neutrally reacting, aqueous solutions may easily be obtained.

Eamnplc .4.

22 parts of 1-allyl-3.7-dimethylxanthine and 33 parts of sodium salicylate are dissolved in 110 parts of warm water. By heating the solution may be rendered sterile and suitable for injections. I

While I have described and claim a process for manufacturing the newly discovered compounds, I desire it to be understood that I claim such compounds .by-whatever process they may be produced and do not limit my claims to such compounds only when produced by such process.

I claim:

1. As new products the double compounds of 1-allyl-3.7-dimethylxanthine which may be produced by allowing at least two molecules of an alkali salt of a benzol-carbonic acid to act upon one molecule of 1-a1lyl3.7- dimethylxanthme, such products being easily soluble in Water, particularly in Warm Water,

their dilute aqueous solutions reacting nontrully and being unaltered oythe addition of alkali, the addition of mineral acids to moderately dilute solutions ofitliese products producing a White crystalline precipitate and such products, upon intense heating,

leaving a solid residue of alkaline reaction;

erately dilute solutions of these products producing a White crystalline precipitate and such products, upon intense heating, leaving a solid residue of alkaline reaction.

3. The process for the manufacture of double compounds of 1-allyl-3.7 -din1ethylxantliine which consists in allowing at least 2 molecules of an alkali salt of a benzolcarbonic acid to act upon 1 molecule of l-allyl-3.7-dimethylxanthine.

l. The process for the manufacture of double compounds of 1-allyl-3.7 -'din1ethyl- Xanthine which consists in allowing at least 2 molecules of an alkali salt of benzoic acid to act upon 1 molecule of l-allyl-3.7-cli. methylxantl ine'. I

In Witness whereof I have licreunto set my hand;

ERNST PREISVVERK. lVitnesses: v

ALBERT ALFRED. Horseman, HENRY KUBLI. 

